WO1991009188A1

WO1991009188A1 - Steel wire for reinforcing the embedding material, especially concrete, and process for making it

Info

Publication number: WO1991009188A1
Application number: PCT/HU1990/000080
Authority: WO
Inventors: Gyula Czomba; László KOVÁCS; Andor LIPTÁk
Original assignee: 'DECEMBER 4' Drótmu^'vek
Priority date: 1989-12-07
Filing date: 1990-12-07
Publication date: 1991-06-27
Also published as: FI922370A; HU204452B; CZ278324B6; ATE118581T1; HUT56308A; EP0504219A1; FI922370A0; SK544590A3; SK278942B6; PL287630A1; DE59008492D1; EP0504219B1; HU896465D0; CZ544590A3

Abstract

Steel wire for reinforcing embedding materials, especially concrete, in which the outline (4) of the cross-section is a three-branched epitrochoid which also has gradually widening and disappearing ribbing (5) along three generatrices with a constant increase in thread pitch, the maximum depth of which corresponds to the difference between the radius (rk) of the circle which can be described around the cross-section and the radius (r¿b) of that which can be inscribed in it.

Description

Steel wire for reinforcing the embedding material, in particular concrete, and the method for producing the steel wire

Field of the Invention

The invention relates to a steel wire for reinforcing an embedding material, in particular for reinforcing concrete, and to the method for producing the

Steel wire.

The steel wire according to the invention not only serves to reinforce the concrete or for prestressing, but it is also possible to use the steel wire in other areas. So e.g. the use of steel wire had also spread to the rubber industry, with some products being reinforced with steel wire, e.g. for conveyor belts, for rubber tires of vehicles. With regard to the fact that the largest amount of steel wire is used in reinforced concrete structures, we will describe the application of the solution according to the invention in connection with the concrete, the viewpoints of the application - analogously - also referring to other areas.

The steel wires commonly used to reinforce concrete structures are obtained directly by rolling or by further processing rolled wires. The steel wires used for prestressing the concrete with a high crack resistance / R _m = 1600-2000 MPa / are cold drawn products.

The steel wire prestressing the concrete is assigned the task that the concrete structure embedding the steel wire can also be loaded with the force that results in it, which causes tensile stress.

Cooperation between steel wire and concrete is guaranteed by the anchoring, which is largely promoted by the framework on the steel wire. Accordingly, the framework is assigned the task of transmitting the force between the concrete and steel wire. State of the art

The framework of the known steel wires that occurs during prestressing, reinforcement of the concrete either has a discontinuous or periodic format, or it has a spiral configuration. The cross section of the steel wire with the periodic skeleton is by no means

constant, since different impressions - repeated - form the skeleton on the outer part of the steel wire, which shows that the cross-section is obviously smaller in the impressions. The steel wire with the spiral structure tends to twist under the influence of the load in the concrete. Elimination or prevention of the twisting is achieved, for example, by distorting the circular cross section of the steel wire, for example by knocking off on both sides, or the skeleton is torn or skeleton strips are designed with the opposite thread pitch. Both in the periodic Skeletons, as well as spiral skeletons, have strong transitions, corners, and it is well known that these are stress-collecting areas where cracks can occur due to the design of the stress peaks. The disadvantages described here occur in the course of use, the periodic skeletons occurring in known steel wires or the distortion of the circular cross section also being considered disadvantageous from the standpoint of manufacture. In the course of the production of the steel wire, the drawing of the

Following the wire, the periodic skeleton is designed or the cross-section deformed in separate work steps, as a result of which in the material of the steel wire the fiber texture - which was created earlier during the drawing process - and the secondary fibrousness is destroyed during the later work steps, as a result of which the mechanical parameters of the steel wire / bending number , Stretching / impaired. As an example of the known solutions we would like to mention the Hungarian patent specification HU-PS 159 837, in which steel wire and the method for the production are described. The solution proposed here is used to produce steel wires with low strength / R _m = 1200 MPa /. In accordance with this solution, the wire rod is drawn cold, after which the gradually expanding and disappearing sloping skeleton is brought about with a cylinder group for flattening and rib design.

One of the disadvantages of the method mentioned is evident the fact that the machining of the profiled cylinders of the cylinder group designing the framework is extremely costly.

The other disadvantage is that the service life of the cylinders is short due to the high load. In the manufacture of prestressing steel wires with high strength / R _m = 1600-2000 MPa / the lifespan of the cylinders is so short due to the increased use that the application seems inappropriate. The Hungarian patent HU-PS 158 074 proposes a solution for the production of high-strength steel wires.

In the sense of the patent specification, two opposing cylinders flatten out - as a pair of cylinders

Wire with the circular cross-section, after which the spiral deformed skeleton with a constant thread pitch is formed on the profiled wire produced in this way, namely with a free-running drawing tool, with a drawing hole with a distorted spiral surface. The flattening is required in this solution because the spiral rib does not in itself guarantee a more satisfactory adhesion to the concrete - due to the twisting, the "drilling" - than the smooth cylinder surface.

With this steel wire, too, there is an edge when the flattened part and the cylindrical sheath part meet, at which point the product tends to crack. Another disadvantage is that the smooth cylinders are difficult due to their high strength can be fitted into the drawing process. Another disadvantage is that the storage cannot be implemented with complete certainty in the case of small dimensions. For the sake of good order, it should be noted that with smooth or with only spiral skeletons, a satisfactory anchoring can only be achieved if these are twisted into strands. The strand can neither twist nor be twisted apart. On the other hand, if several steel wires are used in the strands, additional costs arise, which are also increased by the twisting, since it is a separate operation.

The essence of the invention

The invention sets the goal of eliminating the errors, imperfections and other disadvantages of the known, same-purpose solutions, more precisely, to create a cold-drawn steel wire that has an equivalent framework in all cross sections, none in the foot ends of the framework there are sharp corners, furthermore, which has a characteristic fibrous texture and secondary fibrousness.

The aim of the method according to the invention was that it should not essentially deviate from the customary method of cold drawing, the method should include one simple and cheap means, no additional operations and means should be claimed, in summary, the production should be possible in a single operation, furthermore the usual fibrous texture and secondary fibrousness of the cold drawn wires should not be destroyed.

In the steel wire according to the invention, the set goal is achieved in that the cross section is delimited by a three-armed epitrochoid contour line and has a spiral-like skeleton which has fins which gradually emerge and blur along three production strips.

In essence, the method according to the invention ensures that the set goal is achieved by removing from the wire with a circular cross section in the course of a cold drawing

Process with which a traction tool is used to design the cross section with the epitrochoid contour line, subsequently, on a rotating tool, a cold pulling operation takes place, in the course of which the peculiar drawing hole determines and designs the spiral-like skeleton of the wire and the final cross section of the steel wire.

Based on our tests, we have determined that there can be a maximum of 1.15 between the radii of the revolving circle, the epitrochoid contour line determining the cross section of the steel wire, and the inscribable circle. At the same time the design is considered advantageous if the thread pitch of the ribs is 10-15 times the diameter of the center circle between the aforementioned circles and there are six ribs inside. By the way, this skeleton is spiral and periodic.

The method according to the invention expediently represents a plurality of work steps forming a process. It can happen that the wire serving as the starting piece has to be subjected to a preforming in order to obtain a steel wire with the appropriate surface quality and good dimensions for the work steps according to the invention, which are taken in the narrower sense . A material in such a state is called a preformed steel wire. This designation is also understood if the preforming is unnecessary in the course of implementing the method according to the invention, at least within the course of the method according to the invention, taken in the narrower sense.

In the cold state, the preformed steel wire, which has a cylindrical or circular cross section, is pulled through a stationary drawing tool, the drawing hole of which determines a cross section with a three-armed epitrochoid contour line. The circle that can be written on the cross section has the diameter d _k / the radius r _k /. The cross section of the semi-finished steel wire obtained during the above-mentioned shaping is around 16-30% smaller than that of the preformed steel wire. This means that in the course of pulling on the stationary drawing tool there is a reduction in the cross-section of 16-30%.

Accordingly, the semi-finished steel wire with the cross section with the epitrochoid contour line is pulled through a rotating pulling tool - likewise in the cold state. The drawing hole of the rotating drawing tool has a hexagonal cross section with rounded tips, and has a distorted spiral surface, which results in the skeleton, with a constant thread pitch. This rotating, known pulling tool is free-running and supported in the usual way. For the purposes of the invention, the product that leaves the rotating drawing tool is considered to be a finished steel wire. At the end of the manufacturing process, the finished steel wire can be wound onto the drum.

The tip width l _{k of} the hexagon with the chipped tip in the cross section of the rotating drawing tool corresponds to the diameter of the writable circle d _{k of} the epitrochoid contour line / l _k = d _k /, at the same time the area width l _{b of} the hexagon corresponds to the diameter d _{b of} the writable circle of the epitrochoid contour line / l _b = d _b /. In this way, a skeleton is created on the steel wire by pulling it over the rotating drawing tool. Ratio obliquely to the longitudinal axis of the steel wire, with six cuts, along three generative strips gradually forms and disappears, the height of the ribs making the difference between the two

Radius r _{k of} the writing circle and the radius rb of the writable circle, ie r _k -r _b . Within the framework, the mutual distance between the ribs is 1.6 - 2.5 times the mean diameter, in the contour line of the cross section of the steel. interpreted wire, ie

1.6 d - 2.5 d, where

The maximum height of the ribs is 4-7% of the mean diameter "d" now interpreted. The resulting skeleton becomes without any further technological

Step, designed by pulling on the drawing tools.

In the system for realizing the method according to the invention, the tools required for any preforming, the rollers deflecting and moving the steel wire, as well as the stationary drawing tool and the rotating drawing tool, are expediently arranged in such a way that the steel wire can be designed in a single production process. Of course, the system must be provided with other necessary means known per se, for example for lubrication and cooling, furthermore for the storage of the rotating tool, provide for the organs that absorb axial and radial loads.

The design of the peculiar drawing holes of the drawing tools can expediently be carried out using the spark erosion. procedure. The to the spark erosion process. required electrode can be generated with the system according to the Hungarian patent specification 156 607. In connection with the solution according to the invention, the epitrochoid determination in question is possible according to the following:

x = 4.r _e . cos φ - l. r _e . cos 4 y = 4.r _e . sinφ -l. r _e . sin 4

in which

r _e = the radius of the one that derives the trochoid

rolling circle,

φ = parameter.

Radius of the circle marking the trochoid:

r _k = / 4 + l /. r _e

Radius of the inscribable circle of the trochoids:

r _b = / 4- l /. r _e

The mean radius r = 4.r _e

In practice, the area of the cross section of the steel wire according to the invention, delimited by epitrochoid curves, can be replaced by the area of the circle with the central radius.

The value of parameter l is l = 0.28, it seems appropriate to choose the value 0.18 - 0.19. The essential characteristic of the steel wire according to the invention can therefore be seen in the fact that the contour line of the cross section is a three-armed epitrochoid, the maximum depth of the frame corresponding to the difference in the radius of the inscribing circle of the cross section, along three generative strips and the radius of the inscribed circle, the skeleton gradually unfolds and disappears and is designed with a constant thread pitch.

In an advantageous embodiment of the proposed steel wire, the quotient of the radius of the writable circle of the cross section and the radius of the writable circle is at most 1.15, the thread pitch of the ribs being 10-15 times the mean diameter of the cross section.

The essential characteristic of the method according to the invention can be seen in that the steel wire serving as the output with a circular cross section or a possibly preformed steel wire is pulled through a stationary drawing tool, whereby the cross section is reduced by 16-30% and a semi-finished steel wire with a three-armed epitrochoid contour line is created , after which the semi-finished steel wire is drawn through a free-running but supported drawing tool, which has a constant thread pitch, a distorted spiral surface and a drawing hole with a sexagonal cross-section with rounded tips, in which the Area of the hexagon corresponds to the diameter of the circle, which can be inscribed as an inner tangent to the contour line of the finished steel wire, while the width of the hexagon corresponds to the diameter of the marking circle, which corresponds to the contour of the finished one

Steel wire tangent - corresponds and in which the diameter of the last mentioned writable circle that

Diameter of the concentric circle hitting the tips of the hexagon.

Brief explanation of the drawings

The steel wire according to the invention and the method used for the production are based on the enclosed

Drawings explained in more detail. Show it:

1 shows the cross section of an embodiment of the steel wire according to the invention,

Figure 2 shows the more important components of the system

Implementation of the method according to the invention, FIG. 3 shows the cross section of the steel wire following the preforming and the cross section of the semi-finished steel wire, drawn on top of one another;

Figure 4 shows the cross section of the drawing hole of the rotating drawing tool and the cross section of the semi-finished steel wire, drawn on top of each other.

Preferred implementation of the invention

In the steel according to the invention shown in FIG. 1 wire 9 with the illustrated cross section, the skeleton 5 and the epitrochoid contour line 4 are clearly visible. The circle that can be written around the contour line 4 is shown with a thin line. The diameter d _{k of} the writable circle and the diameter d _{b of} the writable circle are shown. Using this designation, the mean diameter can be determined as follows: d =

where the center radius r corresponds to the value r =.

It is clear from FIG. 1 that the height of the framework 5 corresponds to the difference between the radius of the writable circle r _k and the radius r _{b of} the writable circle, ie r _k - r _b , where r _k = £ and r _b =

Geometric ratios are expediently chosen so that the maximum height of the framework 5 corresponds to the 4 to 7% of the mean diameter.

The sketch according to FIG. 2 represents a possible embodiment of the plant for the production of the steel wire according to the invention. In connection with FIG. 2, the method according to the invention is described in detail. The emerging steel wire 1 represents the material entered as an example. The material must be subjected to a heat treatment, depending on the particular need Surface preparation is required, the cross-section can possibly be changed with the preparatory tools 11. In the course of the operations, the rollers 10 secure the movement, guidance and deflection of the steel wire 1. The operations previously mentioned are known per se and do not belong to the scope of the invention.

In the course of this forming, the cross section of the material gradually decreases, the strength increases. Following a possible preforming, the steel wire is produced, the shaping of which takes place using the method according to the invention - in the narrower sense - taken. This means that the individual preforming operations can take place in separate processes.

The preformed steel wire - which is in the cold state - is pulled through the stationary drawing tool 2. The pull hole has a three-armed epitrochoid cross section. The steel wire 6 entering the stationary drawing tool has a circular cross section, the emerging semi-finished steel wire 8 - as can be seen in FIG. 3 - being profiled. In the course of pulling through on the stationary drawing tool 2, the cross section of the steel wire - depending on the material quality - decreases by about 16-30%. It can be seen from FIG. 3 that the preformed steel wire 6 also has a circular cross section, which can be characterized by the diameter D 'following the preforming. / The diameter D 'the eventu following preforming operations is smaller than the initial diameter D. / The semi-finished steel wire 8 - which is created after the stationary drawing tool 2 - has a cross section with a three-armed epitrochoidal contour line 4. With the help of Figure 4, the method is further explained. The semi-finished steel wire 8 is transformed into the finished steel wire 9 with the aid of the rotating drawing tool 3. The rotating drawing tool 3 has a drawing hole, the cross section of which represents a hexagon with rounded tips. The cross-section has the contour line 7. The drawing hole shows a uniform thread pitch in the axial direction, it has a distorted spiral surface. The rotating drawing tool is supported in a manner known per se, it is free-running. In the case of the hexagon with the contour line 7 and chipped off points, this corresponds to

Point width 1, the diameter d _{k of} the writable circle with the cross section of the semi-finished steel wire 8 with the contour line 4, at the same time the area width 1 corresponds to the diameter of the writable circle / d _b /. The rotating drawing tool 3 is also designed using the spark erosion.

Process.

Finally, the finished steel wire 9 can be wound onto the drum 12 / FIG. 2 /. The for

The required force can be pulled in part by the Drum 12 are exercised.

The steel wire according to the invention, which is produced in the course of the method according to the invention, can have a high strength, for example in the case of a steel wire ∅ 5 mm, the strength is R _m = 1600-2000 MPa.

One advantage of the invention is that the skeleton is designed without any separate technological phase, simply by pulling it on the drawing tools. Another advantageous characteristic is that the steel wire retains the fiber texture created during the cold drawing, the secondary fiberiness, as a result the mechanical properties will be favorable, e.g. the number of bends and the elongation.

Another advantage of the steel wire according to the invention is that slipping out of the embedding material, e.g. Concrete, and torsion through the skeleton is prevented by the epitrochoid shape. With such a geometric design, there are no sharp corners, as a result of which stress-collecting parts in the finished steel wire are avoided.

The steel wire according to the invention can be used as an independent strand or twisted in strands.

Claims

Claims:

1. Steel wire for reinforcing embedding materials, in particular concrete, since it has been shown that the contour line / 4 / of the cross-section is a three-armed epitrochoid, and furthermore has gradually expanding and disappearing skeletons / 5 / with constant thread pitch lying along three generating strips whose maximum depth corresponds to the difference between the radius / r _k / of the writable circle of the cross section and the radius / r _b / of the writable circle.

2. Steel wire according to claim 1, characterized in that the quotient of the radius / r _k / the writable circle of the cross section and the radius of the writable circle / r _b /, ie the quotient can be at most 1.15, the

Thread pitch of the frame / 5 / lo-15 times the

Average diameter / d / of the cross section. -

3. A method for producing the steel wire according to claim 1 or 2, since gekgekzezeic hn et that the starting steel wire / 1 / with a circular cross-section or a preformed steel wire / 8 / through a stationary drawing tool / 2 / is drawn, whereby a semi-finished steel wire / 8 / with three-armed epitrochoid contour line / 4 / and with a cross section reduced by 16-30%, after which the semi-finished steel wire / 8 / is pulled through a supported, but free-running drawing tool / 3 /, which is provided with a drawing hole with a hexagonal and rounded at the tips, with a constant thread pitch and distorted spiral surface, in which the area of the Hexagons / l _b / the diameter of the circle that can be written in as the inner tangent to the contour line / 4 / the finished steel wire / 9 /, while the tip width / l _k / the diameter of the outer tangent to the contour line of the finished steel wire / 9 / corresponds to the writable circle, the diameter / d _k / of the last-mentioned writable circle corresponding to the diameter of the concentric circle which strikes the tips of the hexagon.

4. The method according to claim 3, characterized in that the design in semi-finished steel wire / 8 / and finished steel wire / 9 /, together with any preforming in a single operation.

ABSTRACT

Steel wire for reinforcing the embedding material, in particular concrete, and the method for producing the steel wire The invention relates to a steel wire for reinforcing the embedding material, in particular concrete, and to the method for producing such a steel wire.

The steel wire according to the invention can be characterized in that the contour line of the cross section represents a three-armed epitrochoid and along the three producing strips there are gradually expanding and disappearing skeletons / 5 / with constant thread pitch, the maximum depth of which is the difference between the radius / r _k / of the writable.

Circle of the cross section and the writable radius / r _b / corresponds. Furthermore, the invention relates to a method for producing the steel wire; the main characteristic is shown by drawing the starting steel wire with a circular cross section / 1 / or possibly the preformed steel wire / 6 / through a stationary drawing tool / 2 /, whereby a semi-finished steel wire / 8 / with a three-armed epitrochoid contour line / 4 / and with a cross-section reduced by 16-30%, then the semi-finished steel wire / 8 / becomes a supported one but free-running drawing tool / 3 / drawn; which is designed with a pull hole with constant thread pitch, with a distorted spiral surface and has a hexagonal cross section with rounded tips, in which the area / l _b / the diameter / d _b / of the contour line of the finished steel wire / 9 / als inner tangent corresponds to the inscribable circle, while the tip width / l _k / of the hexagon corresponds to the diameter / d _k / of the inscribing circle - which affects the contour / 4 / of the finished steel wire / 9 / - and the diameter of the inscribing circle / d _k / is equal to the diameter of the concentric circle that strikes the tip of the hexagon.

LIST OF REFERENCE NUMBERS 1 outgoing steel wire

2 stationary drawing tools

3 rotating drawing tool

4 contour line

5 skeletons

6 preformed steel wire

7 contour line

8 semi-finished steel wire

9 finished steel wire

10 scooters

11 preforming tool

12 drum

D output diameter

D 'diameter following the preforming d _k diameter of the inscribing circle r _k radius of the inscribing circle d _b diameter of the inscribing circle r _b radius of the inscribing circle d mean diameter

r middle radius

1 _{k center} distance

1 _{b area} width